In recent years, due to their versatility, trailers have evolved as a preferred way to move goods from one location to another. For example, trailers can be carried or transported in a number of ways, such as over roadways by tractor, over railways on the back of rail cars, or over waterways by ships or barges. In addition, various devices, such as refrigeration units, humidifiers, and anti-shock devices, can be incorporated into trailers for the transport of different products, such as perishable foods, electronics, antiques, chemicals, etc.
In order to monitor, track, control, or otherwise manage such trailers, it is often desirable to communicate with the trailers during transport. Accordingly, various systems were previously developed for transmitting and receiving information from a trailer. These prior systems have proven to be inadequate for one reason or another. For example, some prior systems employed techniques which generated "cross-talk." Cross-talk occurs when one receiving device receives signals which are intended for another receiving device. Cross-talk may result in the mishandling of information conveyed by the signals. Also, despite the presence of the prior systems, trailers were often misplaced or lost. This was especially problematic at any location where the mode of transportation was altered, such as a shipping yard. In addition, in prior systems, the kind and amount of information communicated to and from trailers was extremely limited. Furthermore, prior systems did not consolidate information from a plurality of trailers at a central location, but rather supported communication only proximate each individual trailer, such as in a vehicle transporting the trailer. Previously developed systems also suffered in that they operated in a single mode which caused the systems to constantly consume power, thereby draining any associated power source. This required frequent replacement of the power source, or alternatively, the use of a relatively large source which could supply the needed power.